In Article “Vertical Transportation Design and Traffic Calculations – Part Two”, we indicated
that the Principles of Interior Building Circulation are:
 Efficiency of Interior Circulation,
 Human Factors,
 Circulation and Handling Capacity Factors,
 Location and Arrangement of Transportation Facilities.
Today we will continue explaining other Principles of Interior Building Circulation.
Principles
of Interior Building Circulation

Third: Circulation and Handling
Capacity Factors

The
handling capacity of a vertical transportation system is the
total number of passengers that a vertical transportation system can
transport in a certain period as per certain conditions. In the next sections
we will study how to calculate the handling capacities for the following
items:

1
Corridor handling capacity

The term ‘corridor’ is
defined as the areas whose main function is to provide a connection between
major spaces or operational areas. it include passage ways, walkways, subways
etc. They do not include areas where waiting can occur, such as shopping malls.
The capacity of a straight corridor can be given as:
Cc = 60VDW Equation (1)
Where:
Cc is the corridor
handling capacity (persons/minute)
V is average pedestrian
speed (m/s),
D is the average
pedestrian density (persons/m2),
W is the effective
corridor width (m).
Table1 shows the
Density of persons in Person/ m2 in a corridor and its effect on design.
Table1
Fig.1: Free
and Full Flow Designs for Corridor
The Walking speeds vary
systematically with respect to:
Table2 indicates
empirically derived average Pedestrian speed values as guidance. The table shows the typical pedestrian horizontal
speeds (in m/s) and pedestrian flows in persons per minute (persons/minute) for a free flow design
density of 0.3 person/m2 and a full flow design density of 1.4 person/m2. The flows assume a
corridor width of 1.0 m.
Table2
The width of corridor is
not specific, but must be at least 900 mm and is assumed to be 1.0 m.
Equation (1) allows for the flow rate to increase/decrease as the corridor
width increases/decreases. This factor must be used with care, as small
changes in corridor width will have little or no effect.
Table3 shows Minimum
width for corridors to accommodate various types of traffic. A (3) meter wide
corridor would allow most traffic types to be accommodated.
Table3
Traffic can flow freely
only along unrestricted routes. Corridors are rarely free of obstructions.
For example, a row of seated persons will reduce the effective width of a
corridor by 1.0 m. Table4 indicates the effect of a number of
obstructions.
Table4 shows Reductions
in corridor width due to obstructions.
Table4
Example#1:
In a hospital corridor
it is necessary for two trolleys to pass each other. Each trolley is pushed
by one porter and another person with a bag of equipment walks alongside.
1 What width should the
corridor be?
2 If a row of seated
persons is encountered what effect would this have?
3Indicate the probable
flow rates at free flow design levels.
Solution:
1 From Table3:
For one way traffic; a
trolley and porter occupies 1.0 m width, a man with a bag occupies 1.0 m
width.
If the traffic is two
way, the minimum clear corridor width will need to be at least 4.0 m.
2 From Table4:
If a large obstruction,
such as a row of seated persons, is encountered, the corridor width would
need to be increased by as much as 1.0 m. so, the total width of the corridor
will be 5.0 meters.
3 The circulation mix
would comprise most people moving slowly and a few others on urgent tasks
moving very fast (comparatively). The slow people have a low speed, perhaps
0.6 m/s and the other would probably have a higher speed, perhaps 1.5 m/s. A
reasonable average would be 1.1 m/s. Using Equation (1) the free flow design
rate would be:
Cc = 60VDW = 60 x 1.1 x
0.3 x 60 = 99 person/minute

2 Portal
handling capacity

Portals, which are called
by various names (i.e. gate, door, entrance, turnstile etc), form a division
between two areas for reasons of privacy, security, access control etc. They
represent a special restriction in corridor width. Their main effect is to
reduce pedestrian flow rates. Table5 Portal handling capacities in persons
per minute and persons per hour through an opening of 1m width.
Table5
Note:
Most domestic doors are
less than 1m wide (e.g. approximately 750 mm) and the flow rates would be
likely to be the lower values in the range. Doors in nondomestic buildings
may be slightly wider than 1.0 m and would permit the higher values in the
range to be possible.

3
Stairway handling capacity

The differences between
the movement on stairways and on flat floor are given in below table6.
Table6
Fig.2: Free
and Full Flow Designs for Stairway
Speed of pedestrian
movement on stairway is affected by:
To enable comfortable
walking on a stair, a rule of thumb has been to match the average adult
stride (on a stairway) of about 600 mm with the sum of twice the riser height
(‘rise’) plus the tread depth (‘going’). This results in the following ranges
for efficient design:
An empirical formula for
stairway handling capacity is:
Cs = 0.83
(60 VDW) Equation (2)
Where:
Cs is the stairway
handling capacity (person/min),
V is average pedestrian
speed on the slope (m/s),
D is the average
pedestrian density (person/m2)
W is the effective stair
width (m).
Table7 shows Stairway
pedestrian flows; possible pedestrian flow rates in persons per minute
(person/min) and persons per hour (person/h), and typical pedestrian stairway
speeds along the slope in meters per second (m/s) for a free flow design
density of 0.6 person/m2 and a full flow design density of 2.0 person/m2 for
each1m width of stairway.
Table7

4
Escalator Handling Capacity

(4) Factors affect the Escalator handling capacity as
follows:
A Speed:
The speed is measured in
the direction of the movement of the steps. Most escalators run at one speed
only, although some heavy duty escalators can switchover to the higher speed
during heavy traffic. Escalator s’ available speeds are:
B Step Width:
The available widths
are:
Note:
The hip widths, which
are measured between the skirting panels are typically 200 mm wider than the
step.
C Inclination:
The available escalator
s’ inclination is:
The step tread (going)
and the step rise of an escalator are given in below table:
D Boarding And
Alighting Areas
These areas must
encourage pedestrian confidence and assist the efficient and safe boarding of
escalators. It is recommended that at least 1 1/3 flat step (light duty) to 2
1/3 flat steps (heavy duty) be provided for passengers when
boarding/alighting an escalator. The average pedestrian boarding/alighting
stride can be assumed to be 750 mm.
The theoretical handling
capacity of an escalator (Ce) in person/minute is given by:
Ce =60Vks Equation (3)
Where:
V is speed along the
incline (m/s)
k is average density of
people (people/escalator step)
s is number of escalator
steps/m.
For the case where the
step depth is 400 mm, s becomes 2.5 = 1000/400 and Equation (3) is:
Ce = 150
Vk Equation (4)
The density factor (k)
allows for occupation densities and is taken to be:
Table8
Table9 gives escalator
handling capacity in persons per minute and persons per hour for an assumed
occupancy of two persons per 1000mm step and three persons per two 800 mm
steps and one person per 600 mm step. The horizontal speed is given in meters
per second (m/s)
Table9
Notes:
The actual passenger
density on an escalator is likely to be half this value. Observations showed
that every other step is occupied on a moving escalator. This gives a
standing person an area of two steps, i.e. a space of some 800 mm by 600 mm
in which to stand, which is about 0.5 m2. This is the ‘dense* level of
occupancy of 2.0 person/m2 (see fig.3)
Fig.3
Example#2:
On the London
Underground it was observed, during peak periods, that passengers stood
stationary on the right hand side of the 1000 mm escalator at a density of
one passenger on every other step. The left hand side was occupied by a
walking column of passengers at a density of one person every third step.
Assuming the escalator was running at 0.75 m/s and the speed of the walking
passengers was 0.65 m/s, what is the passenger theoretical and actual flow
rate of the escalator? Noting that step depth is 400 mm.
Solution:
First: The theoretical
handling capacity (flow rate):
1 From Table9 for
speed 0.75 m/s and 1000 mm escalator step width is 13500 persons/hour.
2 For step depth 400 mm
(S = 2.5) and one passenger/ two steps (K =0.5), the flow rate for the right
hand side stationary column from equation (4) will be:
Ce =150 Vk = 150x0.75x0.5 =
56.25 persons/minute = 56.25x60 persons/hour = 3375 persons/hour
3 for the walking
passengers on the left side:
One person for every
three steps, so K = 1/3
And the effective
(relative) speed of the passengers = 0.75+0.65 = 1.4 m/s.
Then the flow rate using
Equation (4) will be:
Ce =150 Vk = 150x1.4x1/3 =
70 persons/minute = 70x60 persons/hour = 4200 persons/hour
So, the total passenger
flow rate = 3375
+ 4200 = 7575
persons/hour.
Second: for the actual
flow rate
We can represent the
escalator case as follows:
Then we have (5)
passengers each (6) steps giving a value for K = 5/6 = 0.83 and the actual
handling capacity of the escalator will be:
Ce =150 Vk = 150x0.75x0.83
= 93.375 persons/minute = 93.375x60 persons/hour = 5603 persons/hour

In the next article, we will continue
explaining other Principles of Interior Building Circulation. Please, keep following.
The
previous and related articles are listed in below table
Subject Of Previous Article

Article

Applicable Standards and Codes Used In This Course,
The Need for Lifts,
The Efficient Elevator Design Solution
Parts of Elevator System Design Process
Overview of Elevator Design and Supply Chain
Process.


The Concept of Traffic Planning,
The (4) Methods of Traffic Design Calculations,
Principles of Interior Building Circulation:
A Efficiency of Interior Circulation


B Human Factors


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